DCRP-59: Signed-Residual Channel Confluence and Rank-Two Identity Closure

Building on DCRP-58's closure of the globally transparent fixed-plane tail (that file itself is missing from the original delivered folder), proves that any exact compensation for DCRP-54's recurring visibility leakage must occur through a finite compensation branch, while DCRP-55/56 show that finite complete compensation forces the accumulated vorticity covariance to become isotropic rank-three.